1. Field of the Invention
The present disclosure relates to a light emitting device that includes a light emitting element with a phosphor.
2. Description of the Related Art
In recent years, light emitting diodes (hereinafter also referred to as LEDs), which provide substantial energy savings, are widely used as light emitting elements instead of filament lamps. Also, light emitting devices are known which include a light emitting element that is formed of gallium nitride (GaN), and a yellow phosphor, for example.
In ordinary lighting fields, a high color rendering is desirable. For example, Japanese Patent Laid-Open Publication No. JP 2004-193,581 A1 discloses a light emitting device that includes a member formed of resin, or the like, mixed with neodymium oxide (Nd2O3) particles. According to this publication, its color rendering index Ra can be increased since light in a specific wavelength range is absorbed. In addition, International Publication No. WO 2011-142,127 A1 discloses a light emitting device that includes glass containing neodymium ions (Nd3+). According to this publication, its color rendering index as well as its luminous efficacy can be improved.
Neodymium oxide and glass containing neodymium absorb light in specific wavelength ranges. Correspondingly, the entire light emission efficiencies of the light emitting devices will be reduced by the absorbed light. From this viewpoint, a light emitting device is desired which has a high color rendering while suppressing the reduction of its light emission efficiency.
The present invention is devised for further improvements. It is one object of the present invention to provide a light emitting device that has both a high color rendering and an improved light emission efficiency.